Development of a Smartphone-linked Optical Biosensing System for Point-of-care Testing Applications

We report a miniaturized batteryless colorimetric biosensing system for measuring saliva components.Our system utilizes a CMOS image sensor and an LED light source embedded in smartphones as a part of the optical system.We measured the concentration of chemical substances by observing color changes of the coloring reagent DA-64, which is specific for hydrogen peroxide.The concentration calculated from the RGB scores of colorimetric images showed strong correlations (r > 0.95) with the concentrations of the samples.This result shows the possibility of biochemical measurements using miniaturized biosensing systems to determine physiological conditions.